WASP-8
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Sculptor |
| Right ascension | 23h 59m 36.0711s[1] |
| Declination | −35° 01′ 52.920″[1] |
| Apparent magnitude (V) | 9.9 |
| Characteristics | |
| WASP-8A | |
| Evolutionary stage | main-sequence |
| Spectral type | G6 |
| WASP-8B | |
| Spectral type | M[2] |
| Astrometry | |
| Radial velocity (Rv) | -1.9±0.6[3] km/s |
| Proper motion (μ) | RA: 109.752[3] mas/yr Dec.: 7.615[3] mas/yr |
| Parallax (π) | 11.1052±0.0175 mas[3] |
| Distance | 293.7 ± 0.5 ly (90.0 ± 0.1 pc) |
| Position (relative to WASP-8A)[2] | |
| Component | WASP-8B |
| Epoch of observation | 2016 |
| Angular distance | 4.520±0.005″ |
| Position angle | 170.9±0.1° |
| Projected separation | 408 AU |
| Details[4] | |
| WASP-8A | |
| Mass | 1.093±0.024 M☉ |
| Radius | 0.976±0.020 R☉ |
| Luminosity | 0.79 L☉ |
| Temperature | 5600±80 K |
| Metallicity [Fe/H] | 0.29±0.03 dex |
| Rotational velocity (v sin i) | 1.90±0.05[5] km/s |
| Age | 0.3+0.9 −0[4] Gyr |
| WASP-8B | |
| Mass | 0.53±0.02 M☉ |
| Temperature | 3758+47 −43 K |
| Other designations | |
| TYC 7522-505-1, WDS J23596-3502A, 2MASS J23593607-3501530, Gaia DR2 2312679845530628096, CD-35 16019[6] | |
| Database references | |
| SIMBAD | data |
WASP-8 is a binary star system of 9.9 magnitude. The star system is much younger than Sun at 0.3+0.9
−0 billion years age, and is heavily enriched in heavy elements, having nearly twice concentration of iron compared to the Sun.[4]
The primary, WASP-8A, is a 9.9 main-sequence yellow dwarf star. It is reported to be a G-type star of temperature 5600 K, mass of 1.093±0.024
solar masses, radius of 0.93 solar radius, and a luminosity of 0.79 of solar luminosity. There is a companion star WASP-8B located 4.5 arcseconds away with the same proper motion indicating a stellar binary system.[7] The stellar orientation is uncertain, but it is a close to pointing one of the poles to the Earth.[8]
Planetary system
The primary star is orbited by two known extrasolar planet, designated WASP-8b and WASP-8c. Planet WASP-8b was catalogued as part of the SuperWASP mission and discovered in 2010 by the astronomical transit method.[7] WASP-8c was discovered in late 2013 by radial velocity method.[9]
Measurements of WASP-8b's radius and mass give it an estimated density of 1.31±0.10 the density of Jupiter. Its measured dayside temperature is 1552 K,[10] much hotter than equilibrium temperature of 947±12 K.[4]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | 2.216±0.035 MJ | 0.0817±0.0006 | 8.159 | 0.3082 | 88.52° | 1.165±0.032 RJ |
| c | ≥9.45 MJ | 5.28 | 4323 | — | — | — |
See also
.jpg?lang=en)
References
- ^ a b Brown, A. G. A; et al. (2016). "Gaia Data Release 1. Summary of the astrometric, photometric, and survey properties". Astronomy and Astrophysics. 595. A2. arXiv:1609.04172. Bibcode:2016A&A...595A...2G. doi:10.1051/0004-6361/201629512. S2CID 1828208.Gaia Data Release 1 catalog entry
- ^ a b Template:Citation=2001.08224
- ^ a b c d Brown, A. G. A.; et al. (Gaia collaboration) (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics. 649: A1. arXiv:2012.01533. Bibcode:2021A&A...649A...1G. doi:10.1051/0004-6361/202039657. S2CID 227254300. (Erratum: doi:10.1051/0004-6361/202039657e). Gaia EDR3 record for this source at VizieR.
- ^ a b c d e A multiplicity study of transiting exoplanet host stars. II. Revised properties of transiting planetary systems with companions, 2020, arXiv:2001.08225
- ^ Bourrier, V.; et al. (2017). "Refined architecture of the WASP-8 system: A cautionary tale for traditional Rossiter-McLaughlin analysis". Astronomy and Astrophysics. 599. A33. arXiv:1611.07985. Bibcode:2017A&A...599A..33B. doi:10.1051/0004-6361/201629973. S2CID 118864447.
- ^ "NAME WASP-8 A -- Star in double system". SIMBAD Astronomical Database. Centre de données astronomiques de Strasbourg. Retrieved 2014-09-29.
- ^ a b Queloz, D.; et al. (2010). "WASP-8b: a retrograde transiting planet in a multiple system". Astronomy and Astrophysics. 517. L1. arXiv:1006.5089. Bibcode:2010A&A...517L...1Q. doi:10.1051/0004-6361/201014768. S2CID 35774603.
- ^ Refined architecture of the WASP-8 system: a cautionary tale for traditional Rossiter-McLaughlin analysis, 2016, arXiv:1611.07985
- ^ FRIENDS OF HOT JUPITERS I: A RADIAL VELOCITY SEARCH FOR MASSIVE, LONG-PERIOD COMPANIONS TO CLOSE-IN GAS GIANT PLANETS, 2013, arXiv:1312.2954
- ^ WASP-8b: CHARACTERIZATION OF A COOL AND ECCENTRIC EXOPLANET WITH SPITZER, 2013, arXiv:1303.5468
External links
- WASP planets
- "Notes for star WASP-8". The Extrasolar Planets Encyclopaedia. Archived from the original on 2008-08-03. Retrieved 2008-08-07.
 | This main-sequence-star-related article is a stub. You can help Wikipedia by expanding it. |